The Soft-Membrane Surface Forces Apparatus

TL;DR

This paper introduces a modified Surface Forces Apparatus designed to measure forces on compliant membranes by analyzing their deformation, enabling detailed rheological and electrostatic interaction studies without external springs.

Contribution

The study presents a novel SFA modification that accurately measures forces on compliant membranes through deformation analysis, advancing experimental capabilities in membrane rheology.

Findings

Effective measurement of membrane deformation fields.

Accurate characterization of electrostatic interactions.

No external measurement spring needed.

Abstract

Compliant walls are widespread in biological and engineering systems. Because of their singular nature, adapted tools are required to accurately study their rheological properties as well as the consequences of the latter within a given mechanical setting. Because of their slender nature, membranes can be considered as prototypical examples of highly compliant boundaries. In this study, we describe a modified Surface Forces Apparatus (SFA) developed to measure the forces acting on a compliant membrane by measuring its deformation field. We discuss how such a device can be used to characterize the rheology of suspended membranes and accurately measure the electrostatic interactions between a polarized membrane and a spherical electrode, without the need of an external measurement spring.